1. Field of the Invention
The present invention relates to liquid crystal displays and manufacturing method thereof; more specifically, to liquid crystal displays.
2. Description of the Related Art
A liquid crystal display (“LCD”) includes upper and lower panels having field-generating electrodes and a liquid crystal layer interposed therebetween. An electric field is generated in the liquid crystal layer by applying electric voltages to the field-generating electrodes. The intensity of the electric field is adjusted to control the transmittance of light passing through the liquid crystal layer, thereby displaying desired images.
An LCD using horizontal electric field includes a common electrode and a plurality of pixel electrodes as field-generating electrodes which are formed on a panel provided with a plurality of thin film transistors (“TFTs”). The common electrode and the pixel electrode generate electric field parallel to the panels for re-arranging liquid crystal molecules to control the transmittance of light passing through the panels. In addition, a polarizer film is typically disposed on the outer surface of the TFT substrate and the color filter substrate.
A TFT LCD has various advantages such as low power consumption, low voltage drive, lightweight, and thin in thickness, etc. The TFT transistor array panel will generally include thin film transistors, pixel electrodes, gate lines and data lines. The color filter panel, on the other hand will generally include color filters and a common electrode. A gate electrode of a thin film transistor array panel is supplied with a gate-driving signal from a gate driver via a gate line which activates the thin film transistor. A data signal applied to a source electrode of the thin film transistor from a data driver via a data line is supplied to the pixel electrode to switch the LCD pixel of the liquid crystal layer.
One measure of LCD performance is viewing angle and much efforts have been devoted to developing wide viewing angles by various wide viewing angle modes. In one viewing angle mode, In-Plane Switching (IPS) is used. In this mode, two electrodes in each cell are mounted parallel to each other and more freely rotate the liquid crystal molecules to align themselves with the electric field, thereby improving viewing angle. Recently, dual domain IPS mode, which dispenses electrodes in a zigzag-like manner, further improves distribution of electric fields and enables LCDs to display the same color from either right or left sides. The dual domain IPS mode overcame the color distortion causing blue shift on one side and yellow shift on the other side. However, true wide angle has not been achieved because the viewing angle cannot amount to 80° or greater, and it is difficult to display gray color in a black state if there is serious yellow shift. In other words, a horizontal field type LCD displaying a black image shows yellow shift from a side view. This is due to the leakage of green and red light from a side view, which deteriorates the display characteristic such as the visibility or contrast ratio. Moreover, due to the yellow shift, viewing angles is narrower, and color characteristic is not the best condition.
A need therefore exists for an LCD having reduced yellow shift in black using parallel electric field, improved contrast ratio in all directions, enlarged viewing angles, and improved color characteristic.